Смотри, тут всё просто:
(5 ⋅ 12 ⋅ 76) : 3 = 5 ⋅ 76 ⋅ (12 : 3) = 5 ⋅ 76 ⋅ 4 = 380 ⋅ 4 = 1520
Ответ: 1520